1. Field of the Invention
The present disclosure relates to a device for detecting attacks by contact on an integrated circuit. This type of attacks is generally called an “intrusion attack” and comprises applying conductive probes directly on areas of the integrated circuit to sample signals therefrom. In an integrated circuit, the active areas contain circuits for processing data which may be confidential, such as for example in bank card chips or access-control chips in toll television applications.
2. Discussion of the Related Art
To protect the circuits located in the active area from any fraudulent intrusion, it is known to use a shield covering the entire circuit surface or part of it. This shield is generally formed of one or of several conductive paths formed in one or several metallization levels above the active area to be protected.
The aim of such conductive paths is to detect a discontinuity or any electric modification of their properties, for example, their resistance or capacitance. The conductive paths run along the entire surface or only an area of the circuit to be protected, in an irregular and random manner. If a “hacker” attempts to cross the metallization level containing the path, by introduction of one or several probes, a detection circuit is supposed to detect a rupture in the conductive path.
A disadvantage of such a solution is that it does not enable to detect the removal of the insulating layers covering the conductive path. Once the conductive path has been exposed, a “hacker” might double this conductive path with an external section to simulate an electric continuity. The conductive path could then be interrupted without this being detected.